Process for producing granular borax



May 3, 1938. H. D. HELLMERS v PROCESS FOR PRODUCING GRANULAR BORAX Filed Jan. 29, 1954 Patented Ma a; 1938 UNITED STATES mam raocass roa rnooocmo Gamma nonex- Henry D. Hellmers, Westend, Application January 29, 1984, Serial No. 708,882

1 Claim.

The present invention relates to an improvement in a process for producing granular borax and the product obtained thereby, and its principal object is to facilitate the commercial 5 handling of borax and to render the same more economical.

Borax at the present time is commercially handled either in the crystalline form of the decahydrate NBaBiO'LlOHzO, or as anhydrous l0 borax NazBaOr. when borax is placed on the market in the form of the decahydrate it carries .a large amount of water, which unnecessarily increases the weight of 'the borax and makes the shipping and other commercial handling of the borax very expensive and the large water content is objectionable in use of the borax for many purposes. It is preferred, therefore, to reduce the decahydrate to the substantially anhydrous borax, before placing the same on the market, and this has been usually done by melting the decahydrate in a furnace for driving oil? the water and by pouring the molten material into molds where it is cooled so as to form a very hard mass that is subsequently 5 crushed or pulverized in any suitable pulverizing equipment.

Molten anhydrous borax poured and cooled to produce a solid mass of this character is very diflicult to reduce and it takes an excessive amount of power for breaking up such borax into a comminuted condition. In breaking up the borax there is also always the danger of contaminating the borax during the crushing operation by particles of metal or whatever substance the crushmg device happens to be made of. It is, for instance, very serious to contaminate the borax with even a small amount of iron, and if such contamination, takes place, the product must be purified again after the pulverizing operation is finished in order to make the anhydrous borax marketable for a good many uses.

I have discovered a much more economical way of treating borax whereby the difiiculties outlined are avoided. In my process I do not 5 discharge the molten anhydrous borax from the furnace and cast it in the form of a solid block, but instead I discharge the anhydrous borax in the form of a comparatively fine thread or thin ribbon, and cause the thread or ribbon to be cooled and broken up into short pieces immediately upon cooling. The borax in cooling breaks itself up into pieces from one to live inches in size. If the anhydrous borax is presented in such a manner it is brittle and can be pulverized very easily in standard reducing machinery.

anhydrous borax or to The preferred form of carrying out my invention is illustrated in the accompanying drawing which illustrates the method of discharging the anhydrous borax from the furnace in the form of a thread, of cooling the thread and of immediately breaking the same into short lengths. When referring to the thread I wish to have it understood that I do not necessarily mean a thread of round cross-section, but that I also wish to cover a thread inthe form of a ribbonor even a thin narrow sheet, the principal object of the inven? tion being to cause the molten dehydrated borax to solidify and to be broken up into thin pieces which lend themselves to pulverizing or comminuting action much more readily'than a solid block. v

While I have shown only the preferred form of carrying out my invention, I wish to have it understood that various changes or modifications may be made within the scope of the claim hereto attached without departing from the spirit of the invention.

In carrying out my invention I first melt the decahydrate of borax in the furnace I, and I continue this heating until anhydrous borax in the molten state remains. Then I discharge the anhydrous molten mass through the spout 2 in the form of a comparatively thin thread or ribbon of molten nhydrous borax indicated at 3. This thread is scharged upon a water-cooled drum 4 which is revolved by any suitable means .and reciprocated axially as by the eccentric 5 so that the descending thread continuously contacts a new portion of the drum whereby it is cooled more I eiliciently. The rate of the rotaryspeed of the 5 drum and the rate of reciprocation are preferably proportioned so that the thread if allowed to remain on the drum would form a spiral there on. However, after a few turns of the drum the thread has become cooled sufliciently to be brittle and mostly breaks up into chunks, and any of the resolidified material that remains attached to the drum is removed from the drumby a scraper or any other suitable instrumentality. The borax when cool will break of its own accord into pieces and the scraper will clean the drum should any of the borax adhere thereto. I preferably arrange the drum 4 somewhat longer than the length of its stroke so as to present an active central area 6 which receives the thread from the spout 2 and two inactive end portions 1 and 8. I also preferably provide two scrapers 9- and I0, spaced by a few turns from the transverse plane of the spout on opposite sides of the plane. The drawing shows the drum in one of its end posi- 66 tions and the spout as discharging on one end of the active area. As'the drum moves to the right and makes a few turns, the first turn of the removes the first turn and continues to remove v additional turns of the spiral as the drum ad-' vances. When the drum reaches the end of its right hand travel, there will be a few turns left on the drum and the left hand scraper will be in contact with the left inactive end of the drum. The drum now reverses its direction and moves to the left which causes the thread to double up on itself through a short distance until the remaining turns have been covered, whereupon the spiral will be continued in a single layer. After the-drum has moved to the left by the width of a fw turns, the first turns of the left hand end of the spiral will reach the left hand scraper 9 and the scraping action will now proceed from left to right. It will be noted that the thread will be broken away from the drum in comparatively short pieces which may be collected and which may be easily pulverized there after in a suitable pulverizer. As above stated the breaking of the borax into small pieces is due to thecooling of the borax.

' could be obtained The advantages of treating borax'in this manner are apparent from the foregoing description. It takes less power to break upv the pieces of thread or thin ribbon than it would to break up a solid mass; the contamination of the borax by the metal of the comminuting apparatus is prevented since less power is required for crushing the borax, less dust is formed during the pulverizing action, and the borax is broken up into particles of more even granular size than by the breaking up of solid blocks of borax.

I claim:

Process of producing anhydrous borax comprising melting and dehydrating borax decahydrate by heat to produce molten anhydrous borax glass; discharging the molten borax glass so produced, in the form of a thin threadlike stream upon the surface of a rotating cooling drum, thereby solidifying and breaking up the glass into relatively short lengths which can be ground without the production of excessive fines or contamination by metallic impurities from the grinding apparatus; and so grinding suchshortlengths.

HENRY D. HELLMERS. 

